Furnace



J. VAN BRUNT.

FURNACE- APPLICATION FILED JUNE 22, I918.

Patented July 18, 1922.

v fw INVENTOR.

BY ATTORNEYS.

between the grate bars after passing througl'i.

the same; or the dampers 15 and 12 may both be opened more or less so that part of the air which passes between the grate bars shall have traversed the grate bars while part passes directly to the compartment 9 beneath the grate bars through ports controlled by the damper 12. Or the damper 15 may be closed and the damper 12 open so that substantially all the air which passes upward bet-ween the grate bars is supplied directly through the damper 12.

16 are the ordinary dump grates located. beneath the outer ends of the grate bars. It sometimes happens that unconsumed carbon reaches the burning out zone 8 above these dump grates and in order that air may be supplied thereto for its proper combustion, I provide the walls 17 of the primary air boxestii with sliding dampers 18 controlled by handles 19 so that air may be admitted from the primary air boxes to the ash pits 20 below the dump grates and, passing upward through the matter supported'thereby, aid in the complete combus tion of any carbon contained therein.

On account oi? unavoidable air leakage between the abutting surfaces upon the outer ends oi? the grate bars and the support for their outer ends when the grate bars contain air under pressure, any unconsumed coke which reaches the dump grates l6, adja cent to the point oi? discharge of such leakage, is liable to become so highly in'candescent as to injure the portions ol the grate bars and dump grates adjacent thereto if such air is allowed to impinge directly upon such coke. In order to prevent such direct impingement in the construction shown, I place on the-lower side of the outer extremities of the grate'bars lips 21, which extend into the path oi the leaking air, breaking up the jets of air and causing it to diffuse and pass through the openings between the grate bars and the dump grates at low velocity, thus reducing the intensity of the re sulting combustion.

Air is supplied to the ducts 'i' from a conduit 22, the supply to those ducts being controlled by valves 23', the conduit and these valves being shown in dots in Fi 2.

From the foregoing it will be seen that there are three separate and distinct pressure compartmentsfrom which the air may pass through the fuel adjacent to each series oi? grate bars. These compartments are re spectively the tubular compartments or hollow. grate bars, from which the tuyeres 4 lead, the auxiliary compartments 9 and the ash pits-20 beneath the dump grates 16, and connections to or from all these compartments are subject to manual control by the dampers -l5, 12 and 18, so that the pressures in those separate compartments may be varied more or less independently. It is also to be noted that the pressure in the compartments on the two sides of the stoker may be varied. independently, the two sides being separated by the wall 10.

WVith the arrangement shown, the air in passing from the main air box 3 to the tuyeres d absorbs the heat from the grate bars, keeping the grate bars relatively cool. The air discharged from the tuyere is heated air. When operating at high ratings or with certain kinds of coal this preliminary heating before discharging into the ignit ing and coking zone 8 is a decided advantage as it improves the ignition particularly with low grade or low volatile fuels or with coals running high in moisture. With this arrangement also the pressure in the compartments 9, S), beneath the grate bars can be increased and din'iinished so as to be independent of the amount of heated air passing through the grate bars, the thickness of the lire above the grates and the space between the grates, thus enabling a sufficient pressure to be maintained beneath the grate bars in order to obtain satisfactory combustion in the combustion zone 8. In case suiti'icient air does not pass through the tuyeres 4- the damper 15 can be closed more or less and "the damper 12 regulated so that the pressure at the tuyeres 4: can be increased to whatever extent is desirable, producing the proper relation between the pressures at the tuyeres and in the chambmr 9 to get satis factory ignition and coking and combustion conditions.

Since by reason of the separation of the two halves ot the system by the wall 10, it ispossible to control the air to the zones on either side of the retort independently of the other, the air can be adjusted on either side so as to increase thecombustion rate on the side where the lire is heavier and bring the fire on that side down to the same thickness on the other side.

When running at extremely low ratings or with thin lllGS, theair pressure in the auxiliary boxes 9 may be reduced or shut o'ii' entirely and substantially the entire combustion carried on in the zone 8.

Since the damperslS make it possibleto admit air directly under the dump gratesit 18 possible to burn out any unconsumed carbon which may remain, assuring that In embodying my invention I prefer to use a retort having a series of grate bars extending from each side as shown, but as will. be evident to those skilled in the art, my invention permits of various modifications without departing from the spirit thereof or the scope of the appended claims.

What I claim is:

i. In a stoker furnace, the combination of a retort, a series of grate bars extending therefrom and having air passages between them, said grate bars being tubular and having on their lower faces ports at both ends, a duct for supplying air to the ports at the ends remote from said retort so as to pass through said bars and discharge from the ports adjacent to said retort, means comprising a damper adjacent to said retort ends for controlling the discharge of air through said last named ports, and a chamber located below the central portion of said bars into which the air from said last mentioned ports discharges when said damper is open, said bars having tuyere openings at their retort ends through which some of the air entering at their other ends discharges.

2. In a stoker furnace, the combination of a retort, a series of grate bars extending therefrom and having air passages between them, said grate bars being tubular and having on their lower faces ports at both ends, a duct for supplying air to the ports the ends remote from said retort, so as to pass through said bars and discharge from the ports adjacent to said retort, means comprising a damper adjacent to said retort ends for controlling the d' charge of air through said last named ports, and a chamber located below the central portion of said bars into which the air from said last mentioned ports discharges when said damper is open, said bars having tuyere openings at their retort ends through which some of the air entering at their other ends discharges, and means for connecting and disconnecting said duct and chamber so as to permit air to pass directly from said duct to said chamber when desired.

3. In a stoker furnace, the combination of a retort, a series of grate bars provided with air passages between them and extending from said retort, said grate bars being tubular and being provided with ports in the lower faces of both ends thereof, a passage for supplying air to said bars so as to enter the ports at their ends remote from said retort and pass through bars and discharge from the ports adjacent to said retort, means comprising a damper located adjacent to the retort ends of said bars for controlling the passage of the air through the .ports adjacent to the retort, a chamber located below the central portions of said bars into which chamber air passing through said bars discharges when said damper is open, said bars having tuyere openings at their retort ends through which some of the air entering at their other ends discharges, dump grates at the ends of said bars remote from said retort, an ash chamber below said dump grates, and means for connecting and disconnecting said passage with either or both of said chambers when desired.

t. In a stoker furnace, the combination of a retort, two series of tubular grate bars extending from opposite sides thereof, the bars of each series having air passagejbetween them, said bars being provided at both ends with ports on their lower faces, ducts for supplying air to the ports at the ends remote from said retort so as to pass through said bars and discharge through the ports at the ends adjacent to said retort, means comprising dampers located adjacent to said retort for controlling the discharge of air from the ports adjacent to said retort, said bars having tuyere openings adjacent to said retort, and chambers located beneath the central portions of said two series of bars respectively into which bars of the respective series discharge air when said dampers are open, said chambers being separated from one another.

5, In a stoker furnace a combination of a retort, a series of tubular grate bars extending therefrom, said bars having tuyere openings at their retort ends, chamber located below the central portions of said bars, and a duct adapted to supply air directly both to the ends of said tubular bars remote from said retort and to said chamber, so that air from said duct may pass directly to and through said bars and discharge through said tuyere openings and air from said duct may pass directly to said chamber and escape therefrom between said bars, said bars having air passages between them.

6. In a stoker furnace a combination of a retort, a series of tubular grate bars eX- tending therefrom, said bars having tuyere openings at their retort ends, a chamber lo- (rated below the central portions of said bars, and a duct supplying air directly both to the ends of said tubular bars remote from said retort and to said chamber, so that air from said duct passes directly to and through said bars and discharges through said tuyere openings and air from said duct passes directly to said chamber and escapes therefrom between said. bars, said bars having air passages between them, and a damper located between said duct and said chamber for controlling the passage of air to said chamber.

In a furnace, the combination of a retort, a series of tubular grate bars having air passages between them, said grate bars being provided on their lower sides and adjacent to their respective ends with ports and having their inner ends supported. adj acentto said retort, a primary air box connected to the ports at corresponding ends of. said tubular grate bars to supply air thereto, a secondary air box receiving air from the ports at the other ends of said tubular grate bars, and dump grates extending from the outer ends of said tubular grate bars, said outer ends being engaged and supported by a portion of one of said air boxes, the engaging surfaces of said portion and of said bars being loc-ated between the dump grates and the ports. adjacent to said outer ends, said outer ends having depending projections situated outside of said portion and extending below the supporting surface thereof so as to deflect downwardly air leaking between said portion and the lower surfaces-0t the outer ends oi? said bars engaged. thereby and thus interfere with the free passage of such air directly to the material upon said dump grates. A

8. In a stoker :t'urnace a con'iloination of a retort, a series of tubular grate bars extending therefrom, said bars having tuyere openings at their retort ends, and ports on theirlower sides adjacent to both ends, a chamber located below the central portions of said bars, and a duct supplying air directly both to the ports in the ends of said tubular bars remote from said retort and tosaid chamber, so that air from said duct passesdirectly to and through said bars and discharges through said tuyere openings and air from said duct passes directly to said chamber and escapes therefrom between said bars, said duct and chamber constituting air boxes, said grate bars having air passages between them, and dump grates,

extending beneathfsaid remote ends. of said tubular grate bars, said remote ends being engaged and supported by a portion of one of said air boxes, the engaging surfaces of said portion and of said bars being. located between the dump gratesand the ports adjacent to said outer ends, said outer ends having depending projections. situated outside of said portion and: extending below the supporting surface thereof so as to deflect.

interiors, a duct ior supplying air to the ports at the ends remote from said retort so that it passes through said. bars and dis charges both from the ports adjacent to said retort and through said tuyere openings, a chamber located below the central portions 01% said bars and adaptedto receive air from said last named ports, and means controlling the flow off air to said chamber comprising a damper located between said last named ports and said chamber. I

, JOHN VAN BRUNT. 

